Messages in this thread Patch in this message | | | Date | Tue, 24 Feb 2009 12:27:19 -0500 | From | Tony Battersby <> | Subject | [PATCH 3/6] [2.6.29] epoll: remember the event if epoll_wait returns -EFAULT |
| |
If epoll_wait returns -EFAULT, the event that was being returned when the fault was encountered will be forgotten. This is not a big deal since EFAULT will happen only if a buggy userspace program passes in a bad address, in which case what happens later usually doesn't matter. However, it is easy to remember the event for later, and this patch makes a simple change to do that.
Signed-off-by: Tony Battersby <tonyb@cybernetics.com> ---
This patch is against 2.6.29-rc6; however, it doesn't need to go into 2.6.29. Use the -mm version instead if applying after the other patches in -mm.
--- a/fs/eventpoll.c 2009-02-20 16:34:02.000000000 -0500 +++ b/fs/eventpoll.c 2009-02-20 16:36:25.000000000 -0500 @@ -974,8 +974,6 @@ static int ep_send_events(struct eventpo for (eventcnt = 0; !list_empty(&txlist) && eventcnt < maxevents;) { epi = list_first_entry(&txlist, struct epitem, rdllink); - list_del_init(&epi->rdllink); - /* * Get the ready file event set. We can safely use the file * because we are holding the "mtx" and this will guarantee @@ -1000,6 +998,9 @@ static int ep_send_events(struct eventpo epi->event.events &= EP_PRIVATE_BITS; eventcnt++; } + + list_del_init(&epi->rdllink); /* remove from txlist */ + /* * At this point, noone can insert into ep->rdllist besides * us. The epoll_ctl() callers are locked out by us holding
| |